The translation of the back and forth, or reciprocating, movements of the pistons of an internal combustion engine into a rotating movement is normally accomplished by a crank gear comprising a crank-shaft and connecting rods. In this arrangement there is the disadvantage that with an increase in rpm and compression, strongly increased friction losses occur in the bearings of the connecting rods, the crank and the crank shaft. Particularly in connection with Diesel engines this limits an increase in compression and rpm, although higher compression ratios would be per se desirable because they would result in higher ignition temperatures and thereby improved combustion. This is desirable because of improvements in efficiency as well as reduction of pollutants in the exhaust gases.